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Potentially Reduced Exposure Products (PREPs)

What is a PREP?

Prior to February 2001, even tobacco industry insiders were generally not familiar with the phrase "Potential Reduced-Exposure Products" or the term "PREPs." All that changed on February 22, 2001, when the Institute of Medicine (IOM) of the United States National Academies of Science, issued its report, "Clearing the Smoke: The Science Base for Tobacco Harm Reduction" (1-3). The IOM had been asked by the United Stated Food and Drug Administration (FDA) in 1999 to consider whether there could be safer tobacco products and how such potentially safer products could be assessed and what would be the impact of such products on public health. In the words of the IOM, the term PREP is used, "when discussing modified tobacco products, cigarette-like products (whether tobacco containing or not), or pharmaceutical products and medical devices (whether nicotine containing or not) developed for their tobacco harm reduction potential. Demonstration of exposure reduction is possible but at this time, demonstration of harm reduction is not (Reference 1 at Page 28)."

While the report made several recommendations that were applicable to both conventional tobacco products as well as tobacco-containing PREPs (e.g. testing and reporting of ingredients, reporting of deliveries of nicotine and other toxicants under conditions that reflect actual human use patterns), its recommendations on PREPs were not as specific as some may have desired. Indeed, the IOM did not give specifics as to the toxicants to be reduced and the extent of toxicant reduction needed for a product to be called a PREP or the assays to be used to show the potential reduction in biological harm expected from a given PREP (Reference 1 at Pages 9-14). For tobacco-containing PREPs, and especially PREPs that are similar to cigarettes, the IOM report did not clarify the situation as to what to remove, how much to remove, and how to show that the removal of a given component or class of component reduced biological activity relevant to smoking-related diseases. It did clarify the situation as to the desirability of PREPs from an overall public health point of view.

In one sense, this left the smokers in 2001 no closer to a reduced-risk cigarette than their predecessors were in 1968 when the joint program [known as the Smoking & Health Program (S&HP)] between the tobacco industry and the National Cancer Institute (NCI) began its quest "Toward a Less Hazardous Cigarette" (4). Unfortunately, that program was reduced in scope before many of the more innovative experiments were completed as the NCI shifted its focus to smoking cessation.

Because the assessment procedures used in the S&HP focused mainly on the "tar" in cigarette smoke, several of the compounds now thought to be responsible for the bulk of toxicity associated with cigarette smoke were probably not assessed properly (5). These compounds include acrolein, carbon monoxide, hydrogen cyanide, and the nitrogen oxides. These compounds are very volatile, and conventional cigarette filters are not very good at removing them. Dr. Gio Gori, who was head of the Smoking and Health Program, used a technique known as risk analysis to estimate the number of cigarettes of a given brand-style that could be smoked without undue risk (6). Gori's views were heavily criticized (7-9). The subject of the less hazardous cigarette was no longer popular in polite company.

It was another decade or so before scientists began talking again about less hazardous products based on conventional cigarette technologies. In this context, conventional means tobacco burning as opposed to tobacco heating or other devices such as Premier, Eclipse, and Accord. In 1995, R. J. Reynolds Tobacco Company introduced Winston Select. This brand-style contained a special charcoal filter as described in a document prepared for the media (10). A more detailed discussion of the filter technology was given at the March 1996 meeting of Canada's Expert Committee on Cigarette Modifications (11).

Research that is much more recent has shown that several very volatile compounds which can be reduced by special cigarette filters (charcoal, in particular) are now thought to be the likely causes of smoking related diseases (12-14). Some smoking-and-health experts have recommended adoption of such filters (15-16). Some experts have based their recommendations on the differences in the incidence of smoking related diseases between smokers in the U.S. and those in Japan, where most of the cigarettes sold have charcoal filters (17-18). Those same authors also point out that in addition to the use of charcoal filters, the tobaccos used in the Japanese cigarettes result in lesser amounts of compounds called tobacco specific nitrosamines (TSNAs) and polycyclic aromatic hydrocarbons in the smoke. Such compounds are in the "tar" part of cigarette smoke and other smoking-and-health experts believe that such compounds are the likely cause of lung cancer (19-20).

With these differences in views among experts as to what should be removed from smoke for a cigarette to be called at PREP, there also is considerable debate on how such PREPs should be evaluated. The Life Sciences Research Office, which is an independent body for expert evaluation of controversial issues in basic and clinical research, has a project underway to evaluate the science base necessary to assess claims for potentially reduced-risk tobacco products (21). The Transdisciplinary Tobacco Use Research Center (TTURC) at the University of Minnesota has also studied the factors to be considered for the evaluation of PREPs (22). Hopefully, all concerned will work together to develop consumer-acceptable cigarette PREPs that have a high potential to reduce smoking-related diseases.

  1. Institute of Medicine, Committee to Assess the Science Base for Tobacco Harm Reduction (2001). Clearing the Smoke: The Science Base for Tobacco Harm Reduction, National Academy Press, Washington, DC. This book can be read online free or ordered (cost) at http://books.nap.edu/catalog/10029.html .
  2. An eighteen-page executive summary of the book is available online without charge at http://books.nap.edu/execsumm_pdf/10029.pdf .
  3. An eight-page briefing on the book is available online without charge at http://books.nap.edu/html/clearing_the_smoke/reportbrief.pdf .
  4. Gori, G. B. (2000). Virtually Safe Cigarettes. Reviving an Opportunity Once Tragically Rejected, IOS Press, Washington, DC.
  5. Slaven, R. W. (1981). A Critical Review of "Toward a Less Hazardous Cigarette," Research from NCI's Smoking and Health Program, Lorillard Research Center Report, Accession number 1657, May 28, 1981. Multiple copies of that report can be found at http://tobaccodocuments.org/all/ssearch/?pattern=author%3Aslaven+nci%27s+review
  6. Gori, G. B. and Lynch, C. J. (1978). Toward Less Hazardous Cigarettes. Current Advances, Journal of the American Medical Society 240(12):1255-59. A copy of that journal article can be found at http://tobaccodocuments.org/pm/1000207157-7161.pdf .
  7. Barclay, W. R. (1978). Smoke Screens, Journal of the American Medical Society 240(12):1281. A copy of that journal article can be found at http://tobaccodocuments.org/rjr/502987153-7153_D1.pdf .
  8. Anonymous (1978). 'Safe-Cigaret' Physician Stands Firm on Report, American Medical News 21(33):2. A copy of that news release can be found at http://tobaccodocuments.org/bw/1004257.pdf .
  9. Greenberg, D. S. (1978). Tobacco Politics: The "Safer" Cigarette Flap, Science & Government Report 8(15):1-3. A copy of that article can be found at http://tobaccodocuments.org/ti/TIMN0110749-0751.pdf .
  10. R. J. Reynolds Tobacco Co. (1995). Winston Select Flavor Filter (Winston EW) for Media Inquiry Only. A copy of the 9-page media statement can be found at http://tobaccodocuments.org/rjr/511388000-8008.pdf .
  11. Rickert, W. S. (1996). Report of Canada's Expert Committee on Cigarette Modifications, Conference Proceedings, March 1-3, 1996, Toronto, Ontario Canada. A copy of the 104-page report can be found at http://bat.library.ucsf.edu/data/i/f/l/ifl60a99/ifl60a99.pdf .
  12. Haussmann, H-J., Rustemeier, K., and Elves, R. G. (2001). The Use of Risk Analysis in Selecting Cigarette Smoke Compounds for Reduction. Poster presented at the Society of Risk Analysis Meeting, Seattle, WA, December 2-5, 2001. A copy of the poster can be found through a search at http://www.pmusa-science.com/biblio/presentations/PresentationSearchResult.asp?DesiredPage=All .
  13. Fowles, J. and Dybing, E. (2003). Application of Toxicological Risk Assessment Principles to the Chemical Constituents of Cigarette Smoke, Tobacco Control 12:424-430. A copy of that journal article can be obtained at http://tc.bmjjournals.com/cgi/content/full/12/4/424 .
  14. Laugesen, M. and Fowles, J. (2005). Scope for Regulation of Cigarette Smoke Toxicity According to Brand Differences in Published Toxicant Emissions, New Zealand Medical Journal 118(1213):U1401. An abstract of that article is available at http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15843830&query_hl=4 .
  15. Slade, J. and Henningfield, J. E. (1998). Tobacco Product Regulation: Context and Issues, Food and Drug Law Journal Supplement 53:43-74. A copy of that journal article is available at http://tobaccodocuments.org/pm/2081367305-7336.html .
  16. Laugesen, M. and Fowles, J. (2005). Scope for Regulation of Cigarette Smoke Toxicity: The Case for Including Charcoal Filters, New Zealand Medical Journal 118(1213):U1402. An abstract of that journal article is available at http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15843831&query_hl=4 .
  17. Djordjevic, M. V., Hoffmann, D., Thompson, S., and Stellman, S. D. (1998). Tobacco and mainstream smoke chemistry of the leading U.S. and Japanese cigarettes, Program booklet and abstracts 52nd Tobacco Science Research Conference 52:42. Verbal presentation at 52nd Tobacco Science Research Conference, Atlanta, GA, September 13-16, 1998.
  18. Stellman, S. D., Takezaki, T., Wang, L., Chen, Y., Citron, M. L., Djordjevic, M. V., Harlap, S., Muscat, J. E., Neugut, A. I., Wynder, E. L., Ogawa, H., Tajima, K., and Aoki, K. (2001). Smoking and Lung Cancer Risk in American and Japanese Men: An International Case-Control Study. Cancer Epidemiology, Biomarkers & Prevention 10:1193-9. A copy of that journal article can be obtained at http://cebp.aacrjournals.org/cgi/content/full/10/11/1193 .
  19. Hecht, S. S. (1999). Tobacco Smoke Carcinogens and Lung Cancer. Journal of the National Cancer Institute 91:1194-1210. A copy of that article can be found at http://jncicancerspectrum.oupjournals.org/cgi/content/full/jnci;91/14/1194
  20. Hecht, S. S., Murphy, S. E., Carmella, S. G., Li, S., Jensen, J., Le, C., Joseph, A. M., and Hatsukami, D. K. (2005). Similar Uptake of Lung Carcinogens by Smokers of Regular, Light, and Ultralight Cigarettes, Cancer Epidemiology, Biomarkers & Prevention 14:693-698. An abstract of that article can be found at http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15767351&query_hl=10 .
  21. Life Sciences Research Office (2005). Evaluating the Scientific Evidence for Potential Reduced-Risk Tobacco Products. See http://www.lsro.org/rrrvw/rrrvw_home.html for more information.
  22. Hatsukami, D. K. and Hecht, S. S. (2005). Hope or Hazard? What Research Tells Us about "Potentially Reduced-Exposure" Tobacco Products, University of Minnesota Transdisciplinary Tobacco Use Research Center, Minneapolis, MN. A copy of that report is available at http://www.tturc.umn.edu/documents/hope_or_hazard-3.pdf .